In various wet processing arts involving chemical treatment, such as etching, electroplating and the like, it is known to deliver fluids onto surfaces of articles being treated. In many instances, the articles being treated are printed circuit boards and the like. Often such articles are being delivered along a generally horizontal path and are etched, cleaned, rinsed, activated, dried, coating, etc., at various stations along the path. Sometime the articles being treated, if they are printed circuit board, have bore holes extending therethrough and it is desired to have the treatment fluid impinge not only on upper and lower surfaces of the boards, but also on bore holes. The treatment of the articles can take place via nozzle arrangements, such as that set forth in U.S. Pat. No. 4,789,405, for example. In other instances the treatments may take the form of various other fluid delivery, spraying, drying techniques, such as those disclosed in U.S. Pat. Nos. 4,576,685, 4,017,982, 3,935,041, 3,905,827, or 3,776,800. Various drive techniques for driving the printed circuit boards or other articles through the various treatment stations may be used, such as those set forth in U.S. Pat. No. 4,046,248 or the like.
Accordingly, the technical field of this invention is directed to a method and arrangement for treating conductor substrates. Such treatment processes can include the removal of liquid from through-holes in conductors boards and from its surface, drying the boards, in addition to cleaning, coating, rinsing, etching, activation and various electrolytic processes.
The present invention is directed toward efficient delivery of fluid to articles being treated, and most particularly to conductor boards and the like.
In connection with the fluid delivery, slotted tubes, for example have been used, but such are limited in development of the flow upon exiting the orifice or slot, such that the flow stream may dissipate more quickly and lose some of its momentum, even exponentially, as the distance from the substrate being treated increases.
Spray nozzles are also use, but such often require large amounts of energy relative to the fluid medium being processed. Additionally, in some instances spray nozzles do not provide the desired level of uniformity in terms of coverage, with a higher percentage of flow and pressure being located at the center of the nozzle spray pattern, and a lesser percentage of flow and pressure outwardly thereof, in that flow and pressure are often substantially reduced as the distance is increased perpendicular to the centerline of the nozzle.
Fluid jet injectors have also been used to produce tight columns of flow, but also generally fail to provide a desired level of uniform and complete coverage of the article being treated. Additionally, small injectors require substantially higher pressure to maintain a desired impact of force on the article being treated, which high force impact may not always be desirable.